Recommendation? Having trouble tuning my 31

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It's a Knifestyle YT

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Apr 1, 2020
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Hey everyone, I recently took apart my Sebenza 31 to fix the rattle of the lanyard pin, and I’m having trouble getting it back to the factory condition.
It is either too tight or too loose. If I tighten the stop pin screws all the way, it becomes so tight that I can hardly even open it one-handed. If I don’t fully tighten the stop pin screws it is fine, but after 20-30 flips it loosens up again.
Any adjustment to the pivot does not do much at all (I assume because of the pivot bushing). Any help would be greatly appreciated, thanks.
 
I pinched a washer first time putting mine together again. Same as yours I couldn't get the action right, blade wasn't centered, and would scrape against the scale. Take it apart again.
 
XL883N said:
I pinched a washer first time putting mine together again. Same as yours I couldn't get the action right, blade wasn't centered, and would scrape against the scale. Take it apart again.
Click to expand...


Could you easily tell you pinched a washer? I haven’t really seen anything that would make me believe I did
 
I’ve had that same problem once in the past with one of my 21’s. Couldn’t see anything, but it was harder than hell to open, was not smooth, and you could actually “adjust” the pivot. Turns out pinched washers make them do funky stuff sometimes. I took it apart again and was a little more careful- smooth as glass ever since. :thumbsup:
 
I would lean towards saying pinched washers as well because it is super easy to do and it can result in a tighter stop pin making the blade hard to open (it can also result in the blade being a bit off center, which would obviously be more visibly apparent with a large than a small Seb.) In Tim's own video, at the very end when he closes the knife, it sounds like he may actually have a pinched washer as you can hear what sounds like the blade contacting the inside of the titanium handle...so it's pretty easy to do, and it can happen with both the sandwich method and CRK's method (I recommend using their method.)

What I have learned (from my own frustrations and failures) is that the secret to avoiding the pinched washers is to ensure that the pivot bushing is inserted in a way in which it protrudes enough on each end to 'grab' into the washers and then maintaining it in that position when reinserting the blade into the handle. The slight protrusions on each end of the pivot bushing then pulls the washers along as there is a ledge on each end to grab them. Depending on the Seb, sometimes it can take a while to find the sweet spot where the pivot bushing is 'wedged' inside in the blade in a way where free movement is restricted (if that makes sense...I am describing it terribly but effectively when the pivot bushing doesn't slide back and forth super easily it's then wedged in enough to stay in place and hold each washer so that it remains inside the bushing and doesn't wind up pinched between the end side of the bushing and the inside of the handle.)

Unfortunately, with a pinched washer, if you torque down very firmly, the soft nature of the washer mean that they can permanently deform under this load. When this happens, if the deformation is significant, the knife will not perform very well even if proper assembly follows. Severely pinched washers can be visibly seen, so you may wish to visually inspect them to make sure they are okay. This is a thread showing their looks - https://www.bladeforums.com/threads/would-you-call-this-a-pinched-washer.1374310/

edit - I just took a Seb apart to take a picture. Here's a pinched washer job I did. This one is pretty minor in terms of impacts, so the knife hasn't been serviced, but it's not quite as smooth now as another small I have without one of these
Screen Shot 2020-07-03 at 4.42.03 AM.jpg
 
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Also, the tolerances are so tight that a little bit of dust when reassembling can cause mallfunction.
 
Use loctite on the stop pin screws and the pivot screw.

Or just send it back. If I lived in the US this is what I would have done.
 
What I find that works for me is instead of using the CRK grease, I use SKF food grade bearing grease which is thicker thus doesn't run so much like CRK grease. This will ensure that the two washers and the pivot bushing from sliding away as and when it is inserted between the titanium slabs. The slabs also shouldn't be loose enough that can result in a pinch washer. For me, the slab screws is loosen 1 full turn when it has reach the end of the thread. As CRK are machined to close tolerances, the little gap is just enough for the blade with pivot bushing/washers to slipped into position without any issues. It is fiddly for the first few tries, but it would be second nature in no time. Btw my Large 21 is a 2014 model and is serving me since end 2014 to present.
 
Pretty much what’s been said above, but also use a wrench on both sides when tightening. Insert and turn the male screw enough to engage the female (no puns). Then, keep the male screw still while tightening the female screw. Tighten the female screw almost all the way and then switch holding the female side still and tighten the male screw the remainder. For whatever reason I’ve had luck doing this. Or maybe I’m insane.
 
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